I just picked up a pair of beyerdynamic 990s pro SE, and plugged into my mobo audio jack and had to turn all volume up to 83% just to get decent sound. Its a new asus Maximus VIII Hero. It states it has a 600 ohm amp but that doesnt seem right cause the cans are 250ohms. Also there is a low static in backround from cranking volume almost to max. Does this seem normal?